This invention concerns improvements in and relating to emitters, particularly, but not exclusively, to emitters for indicating their position to a remote location.
In many cases it is desirable to locate an item or person who has in some way become separated from their expected location. For instance, it is desirable to be able to locate a person separated from a sea-going vessel when that vessel sinks or the person is swept overboard. Other applications may include detecting a person lost in a remote location on land and/or piece of equipment for which remote detection is desirable.
The present invention aims to provide a more readily detectable emitter which is highly portable, reliable and suitable for continuous use without interfering with every day activities.
According to a first aspect of the invention we provide an emitter comprising a power source, light emitting means and radiowave emitting means, the light emitting means comprising a first and second electrode, a dielectric material and an electroluminescent material being provided between the first and second electrodes, the radiowave emitting means comprising an antenna.
Preferably the first and second electrodes and the antenna are provided within a casing. The casing may comprise a length or loop of material. The casing may be incorporated in, mounted on or attached to an item, such as a life jacket.
The antenna may comprise the first and/or second electrode.
According to a second aspect of the invention we provide an emitter comprising a power source, light emitting a means and radio wave emitting means, the light emitting means comprising a first and second electrode, a dielectric material and an electroluminescent material being provided between the first and second electrodes, the radio wave emitting means comprising an antenna, the antenna comprising the first and/or second electrode.
The first and second aspects of the invention may include one or more of the following features or possibilities, independently of one another.
The emitter may be provided as a discrete item or may be incorporated in or on a further item.
The emitter may be mounted on or in or be provided integrally with another item, such as a life jacket.
The emitter may comprise a loop providing the light emitting means and the antenna, the loop being connected to a unit, the unit providing the power source. The unit may further comprise a part of the radio wave emitting means and/or control means.
The power source is preferably a DC source. The source may be a battery. One or more batteries may be provided. The batteries may be of the alkaline and/or lithium type. The power source may be provided together with an inverter or power convertor. The power source may be converted to give between 20 and 400V, more preferably between 70 and 220V. The power source may be converted to give a frequency of between 50 Hz and 2750 Hz and more preferably of between 70 Hz and 2500 Hz.
Preferably a single power source is used for the light emitting means and the radio wave emitting means.
The power source may be controlled by control means. The control means may complete or break the electrical circuit. The control means may close the electrical circuit to give light emission and/or radio wave emission.
The control means may include a manually operated on and/or off and/or on and off switch. The control means may include an automatic on control. The automatic on control may be activated where predetermined conditions are met. The predetermined conditions may be or include emersion of the emitter or part thereof in water, for instance for a predetermined period. The predetermined period may be greater than 5 seconds, greater than 10 seconds or even greater than 20 seconds.
The control means may include selection means for continuous and/or intermittent (flashing) light emission and/or radio wave emission. The light emission may flash at between 20 and 80 flashes per minute.
The control means may include radio wave frequency selection means.
The first electrode may be formed of metal. The first electrode may form a core to the light emitting means and preferably to the radio wave emitting means too.
The second electrode may be provided around the first electrode. The second electrode may be provided about the axis of the first electrode, for instance concentrically there about. The second electrode may allow the passage of visible light through it. The second electrode may be discontinuously provided about the first electrode.
The second electrode may be provided by one or more braided electrical conductors. The braids may define apertures there between to allow the passage of visible light.
The dielectric material may be provided as a layer between the first and second electrodes. The dielectric material may be provided as a sleeve. The dielectric material may be provided around the first electrode. The second electrode may be provided around the dielectric material. The dielectric material may be provided as a concentric sleeve on the first electrode.
The electroluminescent material may be provided as particulate material within the dielectric material. The electroluminescent particles may be homogeneously provided within the dielectric material.
The electroluminescent material may be phosphor.
The light emitted is preferably coherent. The light may have a wavelength of between 480 and 530 nm and more preferably of between 500 and 510 nm.
An outer cover may be provided over the second electrode. The outer cover is at least partially transparent to visible light and may be transparent throughout its extent. The outer cover is preferably waterproof.
The combined light emitting means and antenna may be provided in the form of a strand, fibre or cord. The combined light emitting means and antenna may be flexible. The strand, fibre or cord may have a diameter of between 0.1 mm and 10 mm and more preferably a diameter of between 0.3 mm and 3 mm. The bending diameter may be less than 20 times, more preferably less than 10 times and ideally less than 7 times the diameter of the strand, fibre or cord.
The radio wave emitting means may include a radio frequency transmitter. The radio frequency transmitter may provide between 2 mW and 250 mW into the antenna and more preferably between 20 mW and 150 mW. The radio wave emitter means may transmit at 121.5 MHz and/or 243 MHz. One or more further emission frequencies may be provided.
The antenna may include both first and second electrodes. The antenna may be a looped antenna.
According to a third aspect of the invention we provide an item incorporating and/or provided with an emitter according to the first and/or second aspect of the invention.
The item may be an item of clothing, such as a survival suit, waterproof suit, wet suit, dry suit, diving suit, a coat, a waterproof coat or harness.
The item may be a buoyancy item or aid such as a life jacket, life raft, lifeboat, floatation aid or life belt.